It is the purpose of this project to conceive, conduct and communicate the results of original research in the area of genetic manipulation of mammalian cells using the techniques of cell fusion, cellular hybridization and cybridization to produce unique material for the molecular genetic analysis of cellular events. Of prime importance in the laboratory now is the genetic system in mammalian mitochondria. The mapping of recombinations between mitochondrial DNA molecules is being studied using restriction enzymes and cRNA-DNA hybridization. The several distinctive subspecies of mouse are proving to be adequately marked material for such studies. Transformation of sensitive cell strains for antibiotic resistance by DNA from resistant cell mutants is being explored as a means to introduce new genes into mammalian cells so that the impact of such genetic surgery can be evaluated.